This invention relates to a bicyclo[3.3.0]octene derivative and a process for producing the same.
9(0)-methano-.DELTA..sup.6(9.alpha.) -PGI.sub.1 has a potent platelet aggregation inhibiting action. For example, its action is comparable to chemically unstable PGI.sub.2, when human platelet is employed, and it is a compound which can be utilized as a therapeutic or preventive for various diseases of circulatory organs (see the test examples shown below).
In the prior art, as the process for producing 9(0)-methano-.DELTA..sup.6(9.alpha.) -PGI.sub.1, there have been known (a) the process in which it is produced through the 14 steps using PGE.sub.2 as the starting material [Preliminary Text for Lectures in 103rd Annual Meeting in Pharmaceutical Society of Japan, p. 156, (1983)] and (b) the process in which it is produced from 1,3-cyclooctadiene through 19 steps [Preliminary Text for Lectures in 103rd Annual Meeting in Pharmaceutical Society of Japan, p. 157, (1983)]. The former process has the drawback that the starting material is expensive, while the latter process that the desired product is formed as a racemic mixture. Further, both processes (a) and (b) are also disadvantageously very low in the overall yield.